Pump



. A. SOETEHS PUMP Filed March 19, .X965

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United States Patent() PUMP Raymond A. Soeters, Royal Oak, Mich., asslgnor to Holley Carburetor Company, Warren, Mich., a corporation of Michigan Filed Mar. 19, 1965, Ser. No. 441,078 Claims. (Cl. 103173) This invention relates generally to so-called wobble plate type piston pumps wherein rotary drive shaft motion is converted to axial reciprocating piston motion, and more particularly to a novel roller drive system therefor.

Some prior art piston pumps emply a wobble plate which is tixedly secured to the usual drive shaft while other pumps employ both a cam plate and a wobble plate, the two plates being separated by needle bearings. The cam plate, which is normally secured to the pump drive shaft, is, by virtue of its having non-parallel opposite faces, a relatively heavy and expensive element. In some instances, the cam plate is eliminated by the use of a bent or substantially Z-shaped drive shaft having a wobble plate fitted around the bent portion thereof. This, obviously, results in an expensive shaft-machining operation.

Still other prior art axial piston pumps include a rather awkward and expensive drive comprising an angled socket formed in the end of the drive shaft suitable for receiving a ball-ended, axial projection extending from a piston actuating plate which is thereby caused to move in a circular wobbling orbit without revolving.

Accordingly, a primary object of the invention is to provide a drive system which eliminates sliding friction between the pistons of a piston -pump and the means for actuating the pistons.

Another object of the invention is to provide a drive system which eliminates the above mentioned well-known cam plate, Z shaft and socket arrangements.

A still further object of the invention is to provide a drive system which includes rollers or roller bearings operating between a stationary support and a movable plate so as to provide wobbling motion to and threepoint stable support for the simple disc-shaped plate.

A further object of the invention is to provide such a device which is simple in design, inexpensive to manufacture and efficient in operation.

Other objects and advantages of the invention will become more apparent when reference is made to the following specification and the accompanying drawings wherein:

FIGURE l is a schematic cross-sectional view of a piston pump embodying the invention.

FIGURE 2 is an enlarged cross-sectional view taken along the plane of line 2-2 and looking in the direction of the arrows;

FIGURE 3 is a fragmentary schematic perspective view of a modification of a portion of the FIGURE 2 structure.

Referring now to lthe drawings in greater detail, a piston pump 10 embodying the invention comprises a housing having upper and lower bodies 12 and 14, respectively, the bodies 12 and 14 forming a central charnber 16. The chamber 16 is filled with a suitable uid, where the system is a closed one, or continually supplied from a reservoir, where an external operation is involved.

The lbodies 12 and 14 may be fastened together by any suitable means, such as by bolts 18 located through openings 20 formed in flanges 22 and 24.

A drive shaft 30, which may be driven by any suitable means, extends into the lower body 14 through a cylindrical axial extension 26 thereof and a bushing 28.

ICC

The drive shaft 30 may be supported at its inner end in a boss 32 adjacent the chamber 16, or it could extend through the body 12, in order to actuate some additional device (not shown). A simple disc-shaped plate 34 is loosely fitted around the shaft 30 Within the chamber 16. An angled drive arm 36 (FIGURE 2) is secured by any suitable means, such as a set screw 37, to the shaft 30 within the chamber 16, adjacent the plate 34. A pair of rollers, 38 and A40, are mounted on shafts 41 formed at each of the outer ends of the drive arm 36, as better illustrated in FIGURE 2. The outer rollers 38 revolve in one direction against the bottom face of the plate 34, while the inner rollers -40 revolve in the opposite direction on a support ring 42 formed in or secured to a wall of the lower body 14.

It should be noted at this point that, if the plate 34 is a fiat disc, the inner rollers 40 must be of a smaller diameter than the outer rollers 38 in order that the inner rollers not rub against the plate 34. Should the plate 34 be formed to include a dished central section, as illustrated in FIGURE 1, the rollers 38 and 40 may be the same diameter, as illustrated in FIGURE 2.

It is apparent that the plate 34 will rest not only upon the two outer rollers 38, but, due `to some angle A, say, formed by the angled drive arm 36, also upon some third point, namely, the shelf or ledge 44 formed around the chamber 16 within the lower body 14.

A plurality of pistons 46 are slidably mounted within a plurality of cylinders 48 formed within the upper body 12, the pistons being urged toward the plate 34 by springs 49. While only two are illustrated in FIGURE 1, any number, preferably six or more, pistons 46 and chambers 48 may be provided. Each of the pistons 46 has a stem 50 extending therefrom, preferably through a bushing 52 mounted in an opening through a wall of the body 12 between the -chambers 16 and 48. Each of the pistons `46 may also include a seal ring 54 mounted in a groove `around the outer periphery thereof, in order to prevent leakage therepast as it moves in the chamber 48.

Venting passages 56 serve to communicate between the central chamber 16 and the adjacent piston cylinders 48, beneath the pistons 46. A plurality of passages 58 communicate between the central chamber 16 and the cylinders 48 on the spring side of the pistons 56. Each of the several check valves 60 is urged by a spring 62 against a seat 64 formed at the end of the passage 58 connecting with the cylinder 48. Additional passages `66 communicate between the cylinder 48 on the spring side of the pistonsl 46, and a chamber 68 for-med within the upper body 12. Check valves 70 are urged by springs 72 against seats 74 formed at the outlets from the passages 66 into the chamber 68. The chamber 68 may include one or more controlled outlets 76, to either a closed system or to an external system, depending upon the application involved.

Operation As -the shaft 30 is rotated by some external means, manual or otherwise, the drive arm 36 which, as previously explained, is secured to the shaft 30, will likewise be rotated within the chamber 16, the support rollers 40 riding upon the ring 42. With the drive arm 36 being thus rotated, the rollers 38 will roll along the underside of the plate 34, lifting an edge thereof, as they revolve underneath. Under its own weight, and also due to the downward force of the spring biased pistons 46, one edge of the loosely mounted plate 34 will ride on the ledge 44, the latter serving as the -third support point for ythe plate 34. Obviously, rotation of the shaft 30 will cause plate 34 to move in a circular wobbling orbit, by being progressively lifted and lowered as the drive rollers 38 revolve underneath.

Since the pla-te 34 is loosely fitted around the shaft 30 and since the piston stems 5l) are pressing against the upper face thereof, and in view of the fact that the rollers 33 will roll, rather than slide, along the bottom face thereof, the plate 34 will undergo the above mentioned circular wobbling orbit without itself revolving due to friction with the drive mechanism.

It is apparent that as the plate 34 is lifted, the adjacent piston 46 will likewise be forced into its cylinder 48 against the force of the spring 49 and the iiuid in cylinder 48. This will cause check Valve 79 to be lifted off its seat 74 under the force of the tiuid which is being pumped from the chamber 48 into the chamber 68 via the passage 66. Likewise, its check valve 60 will become simultaneously seated, insuring a positive displacement pumping stroke.

The particular piston 46 which is adjacent the edge of the plate 34 approaching or engaging the ledge 44 will be moving downwardly or out of the cylinder 48, under the force of the spring 49, causing the fluid under the piston to `be vented back to the chamber 16 by way of the passage 56. During this suction stroke, check valve '70 will be closed `and check valve 66 will be open, and fluid will be drawn from the chamber 16 through the passage S8 to refill that portion of the cylinder 48 above the descending piston 46.

From the above description of structure and operation, it will be apparent that rotation of the shaft 30 will cause the drive arm 36 to rotate with the shaft. The pistons 46, of which there may be any desired number, are continuously urged in the suction stroke direction by their associated springs 49. However, as the drive arm rota-tes, the rising edge of the plate, which is mounted loosely on the shaft, causes the pistons on the high side of the plate to be urged in the pumping stroke so as to provide a continuous ow of hydraulic fluid through the discharge passage 76.

A modification of the drive arm assembly is illustrated in FIGURE 3, wherein it may be noted that stacked tapered roller bearings 78 have replaced the aligned rollers 38 and 4t) of FIGURES 1 and 2. The tapered bearings 78 are confined within cages 80 formed in the outer ends of the angled drive arm 36. As seen in FIGURE 3, the shape of each of the cages 8) is such -that the pair of tapered roller bearings 78 are mounted therein above and below one another, rather than along side of one another as was the case with the rollers 38 and 4i?. The bottom tapered bearing rides upon the ring 42, revolving in one direction while the upper tapered bearing rides between the bottom face of the plate 34 and the bottom bearing, revolving in the opposite direction.

It should be apparent from the above discussion that, whether rollers, such as elements 38 and 40, or tapered bearings, such as elements 78, are employed in the invention, there is no sliding action between the bearings themselves or between the bearings and the adjacent support ring or wobble plate. This serves to allow the plate 34 to merely undergo a wobbling orbit without being made to rotate along with the shaft 30. Hence, frictional drag on the drive shaft 30 and resultant wear on the various components is extremely low.

Furthermore, it should be apparent that, inasmuch as the plate 34 is constantly being supported at three points, a very stable condition and efficient operation of the pistons results. Also, since the usual machined cam plate is replaced by a simple drive arm and standard rollers or bearings, the cost of manufacturing is reduced.

While it is perhaps not readily apparent from the above description and drawings, it will be realized from an analysis of FIGURE l that the outermost edge of the wobble plate, as it moves through its wobbling orbit, contacts the ledge along a circular path. The diameter of the circular path, when measured horizontally or in the plane of the ledge is less than the diameter of the outermost edge of the wobble plate. Thus, during one wobbling orbit of the plate 34, the larger circumference of the plate will not have made a complete revolution when contact is made once again with the starting point on the ledge 44. The advantage of this phenomenon is that the piston stems 50 will not continuously contact the same point on the upper face of the plate 34; rather, with each revolution of the drive arm 36, the stems will be contacting the plate 34 at a new point away from the starting point a distance equivalent to the difference in circumferences. This, of course, prevents the possibility of depressions being worn into the upper face of the plate 34, under the stems 50, but still virtually eliminates frictional drag on the drive shaft 30.

While but two embodiments of the invention have been shown and described, it is apparent that other modifications thereof are possible within the scope of the appended claims.

What I claim as my invention is:

1. A pump, comprising a housing, a shaft having one end thereof extending externally of said housing, a plate loosely r.fitted around said shaft, a plurality of pistons, a spring urging each of said pistons into continual contact With said plate, means associated with said shaft and said housing for providing three-point sloping support and drive for said plate, wherein said means includes la ledge formed around the inside of said housing, an arm ixedly secured at its center to said shaft, and a pair of roller bearings mounted at each end of said arm, said arm includes an obtuse tangle formed at its center.

2. A device as described in claim 1, wherein the bearings in each of said pair of bearings are positioned axially adjacent one another.

3. A device as described in claim 1, wherein the bearings in each of said pair of bearings are stacked in a cage formed in each of said ends of said arm.

4. A device as described in claim 3, wherein said bearings are tapered roller bearings.

5. A piston pump, comprising a housing, a shaft having one end thereof extending out of an end of said housing, a drive arm fixedly secured to said shaft within said housing, a ledge formed on an internal wall of said housing adjacent said drive arm, a support plate mounted in said housing around said shaft, a first pair of rollers mounted near the ends of said drive arm and in contact with said support plate, a second pair of rollers mounted on said drive arm adjacent said first pair of rollers, a wobble plate loosely fitted around said shaft, said wobble plate being supported -at the extreme outer portions of one of its faces by said ledge and said second pair of rollers, a plurality of chambers, a piston slidably mounted in each of said chambers, a stem extending from each of said pistons through a wall within said housing, said stem being in continual contact with the adjacent face of said wobble plate, a pair of check valves iassociated with each of said chambers such that one of said check valves is opened while the other is closed by virtue of said piston being raised by said wobble plate.

6. A piston pump, comprising a housing, a shaft having one end thereof extending out of an end of said housing, a drive arm fixedly secured to said shaft within said housing, a ledge formed on an internal wall of said housing adjacent said drive arm, a support plate mounted in said housing around said shaft, two pairs of rollers mounted near the ends of said drive arm, one of eaoh of said pairs of rollers being in contact with said support plate, a wobble plate loosely fitted around said shaft, said wobble plate being supported at the extreme outer portion of one face thereof by said ledge and the other of each of said pairs of rollers, a plurality of chambers, a piston slidably mounted in each of said chambers, a stem extending from each of said pistons through a wall within said housing, said stem being in continual contact with the adjacent face of said wobble plate, a pair of check valves associated with each of said chambers such that one of said check valves is opened while the other is closed by virtue of said piston being raised by said wobble plate.

7. A device as described in claim 6, wherein the rollers in each of said pairs of rollers are positioned axially adjacent one another.

8. A device as described in claim 6, wherein the rollers in each of said pairs of rollers are ltapered roller bearings stacked on top of one another.

9. A positive displacement pump, comprising a housing, a drive shaft mounted axially in said housing and having one end thereof extending externally of said housing, a plurality of cylinders formed in said housing around the axis thereof, the axes of said cylinders being parallel to but spaced from the axis of said housing, a piston mounted in each of said cylinders, spring means associated with each of said pistons normally urging said piston in the suction stroke thereof, la plate mounted loosely on said shaft so as to be capable of motion independent of rotation of said shaft, said springs urging said pistons into engagement with said plate, a drive member secured for rotation with said shaft, said drive member being disposed between said plate rand the adjacent end of said housing, said driving member having a pair of arms, each of said -arms having mounted thereon a pair of coaxial rollers, the outer roller adapted for anti-friction rotational engagement with said plate and the inner roller being adapted for antifriction rotational engagement with said housing, said elements being arranged in a manner so that rotation of said shaft causes a wobbling, non-rotational movement of said plate whereby said pistons are successively moved in pumping strokes by said plate.

10. A pump, comprising a housing, la drive shaft mounted axially in said housing and having one end thereof extending externally of said housing, a plurality of cylinders formed in said housing around the axis thereof, the axes of said cylinders being parallel. to and spaced from the axis of said housing, a piston mounted in each of said cylinders said pistons being movable in one direction for the suction stroke and in the opposite direction for the pumping stroke, spring means associated with each of said pistons normally urging said piston in one of said directions, a plate mounted loosely on said shaft so as to be capable of motion independent of rotation of said shaft, said springs urging said pistons into engagement with said plate, a drive member secured for rotation with said shaft, said drive member being disposed between said plate and the adjacent end of said housing, said drive member and said housing being formed and cooperating to provide a three point support for said plate, said drive member having anti-friction rotational engagement with said plate and said housing, said elements being arranged in a manner so that rotation of said shaft causes a wobbling, non-rotational movement of said plate whereby said pistons are each moved in alternating pumping and suction strokes.

References Cited by the Examiner UNITED STATES PATENTS 1,659,238 2/1928 Boyce 230-186 2,374,595 4/1945 Franz 74--60 2,672,095 3/ 1954 Lucien et al. 74-60 2,913,911 11/1959 Gilkey 74-60 3,129,702 4/1964 Arbanas 103--173 DONLEY I. STOCKING, Primary Examiner.

MARK M. NEWMAN, Examiner.

ROBERT M. VARGO, Assistant Examiner. 

1. A PUMP, COMPRISING A HOUSING, A SHAFT HAVING ONE END THEREOF EXTENDING EXTERNALLY OF SAID HOUSING, A PLATE LOOSELY FITTED AROUND SAID SHAFT, A PLURALITY OF PISTONS, A SPRING URGING EACH OF SAID PISTONS INTO CONTINUAL CONTACT WITH SAID PLATE, MEANS ASSOCIATED WITH SAID SHAFT AND SAID HOUSING FOR PROVIDING THREE-POINT SLOPING SUPPORT AND DRIVE FOR SAID PLATE, WHEREIN SAID MEANS INCLUDES A LEDGE FORMED AROUND THE INSIDE OF SAID HOUSING, AN ARM FIXEDLY SECURED AT ITS CENTER TO SAID SHAFT, AND A PAIR OF ROLLER BEARINGS MOUNTED AT EACH END OF SAID ARM, SAID ARM INCLUDES AN OBTUSE ANGLE FORMED AT ITS CENTER. 